Validate Permissions After Migration: Mistakes to Avoid

After migrating SharePoint content to a new environment, permissions often break silently. Users may lose access to libraries, items, or entire sites without any error message. This article explains why permission validation after migration is critical and lists the most common mistakes that cause access failures. You will learn which settings to check and how to verify permissions correctly.

Why Permissions Break During Migration

SharePoint migrations often involve moving content between tenants, site collections, or web applications. During this process, the underlying permission structure can change in unexpected ways. Direct user assignments may be replaced with group membership. Broken inheritance may become inherited again. External sharing links may expire. These changes happen because migration tools do not always preserve the full permission topology. The result is a mismatch between what the site shows and what users can actually do.

Permission validation after migration is not optional. It is the only way to confirm that every user and group has the correct access level on every site, library, folder, and item. Skipping this step leads to help desk tickets, lost productivity, and security gaps.

Steps to Validate Permissions After Migration

1. Review site collection permissions in the admin center
   Open the SharePoint admin center. Go to Active sites. Select the migrated site. Click Permissions. Check that the site collection administrators and primary administrator are correct. This step ensures that at least one person has full control over the site.
2. Check inheritance status for each site
   Navigate to the site. Go to Site Settings > Site permissions. Look at the Permission Inheritance section. If the site shows Inherited Permissions, the site uses the parent site’s permission settings. If the site should have unique permissions, click Stop Inheriting Permissions. Then add the required users and groups.
3. Verify library and item permissions
   For each library, open Library Settings > Permissions for this document library. Check if inheritance is broken correctly. If a library should have unique permissions, confirm that the correct groups appear. Repeat this for folders and items that need custom permissions.
4. Use the Check Permissions tool
   Go to Site Settings > Site permissions. Click Check Permissions. Enter a user name or group name. The tool shows the exact permissions that user or group has on the site. This is faster than manually comparing group membership.
5. Test access with a non-admin account
   Log in with a regular user account that does not have site collection admin rights. Try to open the site, libraries, and items. Note any access denied errors. This real-world test catches issues that the Check Permissions tool might miss, such as broken links or expired sharing invitations.

Common Mistakes When Validating Permissions After Migration

Assuming inherited permissions are correct

Many administrators assume that because the parent site permissions are correct, all child sites and libraries will also work. This is false. Migration tools can reset inheritance on some objects while leaving it intact on others. Always verify inheritance at every level where custom permissions are required.

Not checking SharePoint groups before migration

SharePoint groups like Members and Visitors may contain stale or incorrect members after migration. If the migration tool does not map users correctly, group membership can be empty or contain users from the old environment. Review each group’s membership list and remove orphaned entries.

Overlooking external sharing settings

External sharing links and guest access do not always survive migration. If you rely on sharing links for external partners, test each link after migration. If a link no longer works, create a new sharing link and update the external user’s permissions.

Skipping permission reports

Manually checking permissions on 50 sites is error-prone. Use a permission reporting tool such as the SharePoint Online Management Shell or a third-party report. Generate a CSV report that lists every user, their permissions, and inheritance status. Compare this report to the pre-migration permissions to find differences.

Forgetting to reapply unique permissions after migration

Some migration tools reset unique permissions to inherited. If a site or library had unique permissions before migration, you must break inheritance again after the migration completes. Then reapply the correct user and group assignments.

Pre-Migration vs Post-Migration Permission States

Item	Before Migration	After Migration
Inheritance status	Unique on library	Inherited from site
Group membership	5 members	0 members or wrong users
External sharing links	Active for 3 partners	Expired or missing
Site collection admin	Primary admin assigned	No admin assigned

This table shows the most common permission changes that occur during migration. Each row represents a setting that must be validated after the migration completes.

After migration, always run the Check Permissions tool for each critical site. Compare the results to a pre-migration snapshot. If you do not have a snapshot, create one before your next migration. Use the SharePoint Online Management Shell to export permissions to CSV and store the file in a secure location.

For large migrations, schedule a permission validation window immediately after the content move completes. Do not announce the migration as complete until every site, library, and item passes the permission test. This prevents user frustration and reduces the number of access-related help desk tickets.